POLICE and fire service experts are investigating after a blaze broke out in a house containing a suspected cannabis farm on a Bradford street.

It is believed the fire had burned undetected for a long period at the back-to-back terraced house in Seaton Street, Barkerend, before firefighters were called.

They found the fire burning fiercely and broke bedroom windows to get access for a positive pressure fan to put into action to clear fumes so firefighters could tackle the flames.

It appeared to have started around the staircase on the first floor of the house and had been burning for so long that areas of floor boarding on the first and second floors had been burned away, leaving a potential hazard for firefighters who had to bridge the gaps using extension ladders.

Smoke alarms in the rented property had gone off and were sounding when firefighters arrived but the appeared to have gone unheard by neighbours until the fire had developed.

Firefighters were called at about 1 am on Saturday and two crews from the Bradford station were involved in the operation to douse the flames.

A brigade spokesman said they were at the scene for about four hours and the cause of the fire was still unknown and being investigated by West Yorkshire Fire and Rescue Service investigators and West Yorkshire Police. Scenes of crime investigators were at the property hours after the fire.

West Yorkshire Police confirmed they had been called to the incident after firefighters attended and uncovered "what appeared to be a cannabis farm".

A police spokesman said: "No-one was inside the property at the time of the blaze which caused significant damage to the upstairs floor.

"Work remains ongoing today to make this property safe and examine the suspected cannabis farm.

"Investigations into the cause of the fire remain ongoing by West Yorkshire Fire and Rescue Service," he said.

A fire and rescue service spokesman said: "When we got there we were told the property was empty but we had to check all the rooms as a precaution to make sure there was no-one inside.

"The landlord was there by that time. The fire had been burning fiercely and it caused a lot of damage to the property," he said.

Although the investigation was continuing, it appeared the fire may have started under the floorboards on the first floor.

The building was too badly damaged to be occupied until repair works have been carried out.

Positive pressure fans are used by firefighters to drive fumes from burning buildings, which can assist the firefighting operation and also help to clear the way for occupants to return.